(a) Field of the Invention
The invention relates to a wheelchair and, more particularly, to a new wheelchair that is adjustable in length, width and height in order to be adapted to different users of different sizes or to a child growing up.
(b) Description of Prior Art
There are many different kinds of wheelchairs, many of which are provided with features that allow them to be adapted to different situations or different users.
Presently available wheelchairs are not provided with adjustable characteristics in such a manner that the same wheelchair could be used comfortably or with security by a child or an adult. Most of the wheelchairs are adapted to accept or adapt to small variations in weight or size. In some cases the wheelchairs, by construction, will accept small variation and in some other cases the wheelchairs are adapted to accept larger variations by using different interchangeable and adaptable components, such as the wheelchairs described in U.S. Pat. No. 4,351,540.
Most wheelchairs have rigid frames and have little or no suspension. On uneven ground, a rider will be subject to a rough ride, unless the wheelchair is equipped with a suspension, and still, such wheelchair cannot provide a smooth ride.
Some wheelchairs are adjustable in length allowing for the distance between the front and rear wheels to be adjusted. For example, U.S. Pat. No. 4,892,166 proposes a wheelchair for the handicapped, and in particular to a novel means for removably coupling front wheel portions and rear wheel portions to obtain assembled wheelchairs having various different functions. In one embodiment of the invention, the connection between the front and the rear portions are provided by telescopically related horizontal square tubes.
Some other wheelchairs are provided with adjustable seats or other devices allowing them to be adjusted in height to fit different users of different heights. U.S. Pat. No. 3,618,968 proposes a patient-operated wheelchair in which vertical adjustment of position is provided so that the user of the wheelchair in a seated position would be able to elevate himself so that his upper torso would be at a height equivalent to a standing position.
U.S. Pat. No. 3,672,722 discloses a wheelchair having a seat which can be adjustably positioned between the frame members of the wheelchair
Some wheelchairs are adjustable in width allowing for the transverse distance between the side wheels to be adjusted. For example, U.S. Pat. No. 4,592,570 proposes an ultra light chair having a seat frame separate from a main frame with seat mountings permitting longitudinal, tilt and height adjustment of the seat on the main frame.
U.S. Pat. No. 4,613,151 discloses a wheelchair adapted to provide enhanced mobility for an occupant together with making ground level activities available. The wheelchair comprises a frame that is adapted to be extended upwards or collapsed on itself in order to raise or lower the seat of the wheelchair.
U.S. Pat. No. 4,082,348 proposes an adjustable wheelchair which facilitates independent seat height and width adjustment to accommodate varying wheelchair size needs.
U.S. Pat. No. 4,730,842 proposes an adjustable wheelchair to accommodate changes in the size of an individual, such as a growing child. Accordingly, the seat portion of the wheelchair is adjustable in width continuously over a widely defined range. Furthermore, the seat of the wheelchair is adjustable vertically.
U.S. Pat. No. 4,955,624 proposes a wheelchair with a height-adjustable seat.
U.S. Pat. No. 4,813,693 proposes a wheelchair for a child which grows and expands with the child. The wheelchair may be used to custom-fit wheelchairs to adults, enabling it to be used by adults or children of different sizes. Accordingly, the wheelchair is adjustable in width while retaining constant height.
U.S. Pat. No. 5,020,816 proposes a wheelchair having opposite side frames which comprise individual frame sections which are connected by a longitudinally and angularly adjustable joint allowing for adjustable width of the wheelchair.
As apparent from the above, many adjustable devices exist for wheelchairs. The most common device is the adjustability which allows the seat to be raised, lowered, tilted or inclined in different positions for different users. Some other wheelchairs, in order to allow expansion with the user, are provided with chairs of adjustable length. In this case, the front wheels may be adjusted more or less distant from the rear wheels. In some cases, an adjustment is provided to increase or decrease the distance between the two main wheels of the wheel chair, that is generally the rear wheels.
In any event, none of the prior art described above discloses a wheelchair which is capable of being adjusted in length, in width and in height either by elevated or lowering the seat or increasing or lowering the distance between either the rear set of wheels or between the rear and the front set of wheels or of all these possibilities altogether.